Apparatus for moving tow



Nov. 12, 1963 J. w. SMITH 3,110,432

APPARATUS FOR MOVING TOW Filed Sept. 12, 1960 2 she ets sheet 1 Fig.

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ATTORNEYS 26 JOHN w sM/TH' NOV. 12, 1963 w, SMITH 3,110,432

APPARATUS FOR MOVING TOW Filed Sept. 12, 1960 2 Sheets-Sheet 2 IN V EN TOR.

f I 0 34 I JOH/V n. SMITH United States Patent 3,110,432 APPARATUS FOR MOVING TOW John W. Smith, Kingsport, Tenn, assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Sept. 12, 1960, Ser. No. 55,368 Claims. (Cl. 226-193) The present invention relates to apparatus for continuously moving crimped, continuous filament now. It is particularly useful for pulling tow under relatively high tension to a delivery point for delivery under relatively low tension.

In the manufacture of baled, crimped continuous fila-- rnent tow, it is customary in moving the tow from the area of the plant in which it was fabricated to the packaging area, to move the tow continuously as its fabrication is completed, to a point above a baling apparatus, from Where it is laid in the baling apparatus in a predetermined pattern by lowering it under the influence of gravity while traversing the lowering apparatus to obtain such pattern. Such a tow baling method is disclosed and claimed in Guenther and Smith U.S. Patent No. 2,947,241, issued August 2, 1960, and an apparatus useful for such tow baling is disclosed and claimed in Guenther and Smith US. Patent No. 2,947,242, issued August 2, 1960, to both of which patents reference is made. In textile factories in which baled tow is manufactured the baling apparatus may be located at a relatively long distance from a point at which fabrication of the tow is completed. The top of the baling apparatus also may be at a substantially higher elevtion. As a consequence, when the tow is pulled to the baling area, a relatively high degree of tension is developed in the tow, sufiicient to straighten out the crimps in the fibers. When the pulling is accomplished by means of a pair of rolls positioned above the baling apparatus, difficulty is encountered when the tow is released from the nip of the pulling rolls to be lowered into the baling apparatus under relatively low tension. Upon such release of tension, the crimps return to the fibers of the tow more or less instantaneously, resulting in relative movement of contiguous fibers, and thus a nibbing together of fibers, which in turn causes a build up of static electricity in the tow, making it diflicult to lay the tow properly in the baling apparatus.

The principal object of the present invention, therefore, is to provide a method and means for eliminating difiiculties which result when moving tow isdischarged from a Zone of relatively high tension into a zone of relatively low tension. Another object of the invention is .to provide an apparatus suitable for pulling tow to baling equipment and for deliveting the thus pulled tow to the equipment. Other objects will be obvious from the present specification and claims.

I have discovered that the aforementioned difficulty can be substantially overcome if the tow is pulled successively by and through two or more roll nips having difiering operating characteristics of such nature as to provide a lower linear speed of the tow through a nip than through the next preceding nip. Such a characteristic may be, for example, nip-size, whereby there is greater tow slippage in one nip than in the next preceding, smaller nip, or such characteristic may be surface speed of the rolls forming the nip, whereby tow is pulled more slowly by a nip than by the next preceding nip, which has a higher roll surface speed. In any event, the invention provides for reduction of tow tension through an intermediate stage. That is, the pull of rolls forming a second nip is such that tow extending between the first and second nips is under a tension less than that of tow received by the first nip but greater than that of tow discharged by the second nip.

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In a preferred embodiment of the invention, tow is pulled by and through two successive nips formed by cooperating rolls, the second nip being more open than the first, permitting a predetermined amount of slippage of the tow passing therethrough.

' The invention is illustrated in the attached drawings in which:

FIG. 1 is a schematic perspective view of tow pulling means of the prior art,

FIG. 2 is a schematic perspective view of a tow pulling means of the present invention,

FIG. 3 is a diagrammatic representation of the roll spacing of the apparatus of FIG. 2,

FIG. 4 is a schematic side elevation of a different operating arrangement of the apparatus of FIG. 2, and

FIGS. 5 and 6 show further modifications of the invention.

With reference to FIG. 1, apparatus of the prior art is illustrated in use for delivery of tow 1 to a container 5, such as a hold-up bin for a baling press into which the tow is being laid in a predetermined pattern. The tow normally would be under relatively high tension as it reaches driven rolls 2 and 3 after passing over a stationary guide or idler roll 4. The pulling rolls 2 and 3 are driven in the directions indicated by the arrows and cooperate to obtain a firm' bite on the tow for the purpose of moving it. Inasmuch as the point from which the tow is being pulled may be a considerable distance away and, for example, a number of feet lower than the pulling point, sufficient tension thus is developed in the tow under the influence of the pulling rolls to straighten out the crimps in the fibers of the tow. Upon discharge of the tow from the rolls 2 and 3, the tow falls into the hold-up bins under relatively low tension, i.e.-only such tension as results from the weight of the tow extending from the nip of the rolls down to the surface of the body of tow in the bin. As is customary in the art, the rolls 2 and 3 are oscillated as a unit (by means not shown) along each of two perpendicular horizontal paths so as to provide a uniform pattern of tow within the bin 5. Static electricity developed in the tow as the latter is discharged from the pulling rolls creates difliculties which often make it impossible to lay the tow properly in the bin. Such difiiculties manifest themselves particularly when attempt is made subsequently to withdraw tow from the bale thus formed.

A preferred embodiment of the invention is illustrated in FIG. 2, in which a tow 11 is shown approaching from the left of the drawing over a stationary guide or idler roll 12 and thence to a pulling unit comprised of three rolls 13, 14 and 15 mounted in fixed, spaced relation on parallel axes and cooperating to form two successive nips for the tow, i.e. the first nip being between rolls 13 and 14 and the second nip being between the rolls 14 and 15. The rolls are rotated at a common speed by means of a motor 16 which turns a pulley '17 which by means of a belt or chain 18 drives a pulley 19 fixed to a shaft 20 to which the roll 14 is also fixed. On the end of the shaft 20 opposite the pulley 19, a driving gear 21 is keyed to the shaft 20. Meshing with the driving gear 21 are driven gears 22 and 23 through which the rolls 15 and 13 respectively are driven, the driven gears and their corresponding rolls being fixed to the shafts 24 and 25 respectively. As shown in the drawing, the tow passes toward the right hand side thereof over the roll 13 around and under the latter and up through the nip formed by the roll 13 in cooperation with the roll 14. The spacing of the rolls 13 and 14 with respect to each other is sufficient to provide a bite which will insure positive movement of the tow. From the nip of rolls .13 and 14, the tow passes over the top of roll 14 and down into a nip formed between the rolls 14 and 15, the tow being discharged from such nip to fall from its own weight downwardly into box or bin 26. he size of the nip determined by the spacing of rolls 14 and 15 is such as to allow a predetermined amount of slippage of the tow in the nip. The result of such slippage is that the tow passing over the top of roll 14 is under tension of a degree intermediate that of the relatively high tension of the tow on roll 13 and the relatively low tension of the tow lowered into the box 26 from the nip of the rolls 14 and 15. The development of -a substantial static charge on the tow is reduced to an extent which substantially eliminates adverse changes in the character of the tow delivered to the bin 26.

The spacing of the rolls of the apparatus of FIG. 2 is illustrated diagrammatically in FIG. 3 in which the size of the nip between the rolls 13 and 14. is designated as A and the size of the nip between the rolls 14 and 15 is designated as B, B being greater than A. The absolute sizes of the nips will, of course, depend upon factors such as roll diameter, the nature and size of the tow, tow speed, tension necessary to pull the tow, and the like. I have found that rolls having a diameter of 8 to 9 inches are satisfactory, particularly for use, for example, with a crirnped cellulose acetate tow of 1.6 denier per filament and 37,000 total denier. With such a tow, using stainless steel rolls of 8.5 inch diameter and a tension of 300- a 400 grams on tow moving at 600 meters per minute, the

nip A may advantageously be 0.020 inch and the nip B 0.045 inch. Proper roll spacing may be found for a given tow by providing an adequate pulling bite for the first, i.e. entering nip and approximately slippage for the second, i.e. discharging nip, with respect to tow pulled by it from the first nip. With a given tow, it is helpful to vary the size, and thus the slippage, of the second nip while observing trial runs of the tow and determining the optimum slippage, i.e. the slippage which results in development of least static electricity. In order to vary the nip size, the roll shafts may be mounted in pillow blocks 27 such as illustrated in FIG. 4, which may be fastened to support 28 by any known means which will permit adjustment in the spacing between the outer rolls and the center roll 14. For example, the pillow blocks may he bolted to the support 28 through elongated holes in the latter which will permit movement of the blocks toward or away from the center roll When the nuts on the bolts are loosened. With such a mounting, the desired spacing may be obtained through the use of a spacing gauge.

FIG. 4 illustrates a different threading path for tow passing through the rolls in accordance with the invention. It will be noted that roll spacing differs from that of FIG. 3 so that the relative size of the entering and discharging nips remains the same, i.e. the nip A through which the tow first passes provides -a firm bite on the tow for pulling the same under tension while the nip B permits the desired degree of tow slippage therein.

FIG. 5 shows still another method of tow threading in which the tow 11 enters pulling nip E, passes over center roll 14, and immediately through nip F to discharge.

In the embodiment of FIG. 6, three rolls 31, 32 and 33 have been arranged in vertical alignment to term an entering nip C and a larger, slippage nip D, from which tow 34 is discharged under relatively little tension.

The invention has been described in detail with particular reference to the preferred embodiments thereof, but it will he understood that further variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. Apparatus for moving tow under relatively high tension and delivering the tow under relatively low tension comprising a plurality of driven rolls arranged in spaced relation to provide a plurality of nips for pulling tow, each of said nips being formed by two of such rolls turning in opposite directions substantially at a common surface speed, the rolls which forma second nip being spaced farther apart than the rolls forming a first nip whereby the rolls forming the second nip pull tow received from a first nip through said second nip at a lesser linear ratethan the tow is pulled through said first nip.

2. Tow moving apparatus comprising a trio of rolls mounted in fixed spaced relation on parallel axes, and

means for driving all three rolls at a common surface speed, two or" said rolls cooperating to form therebetween a nip of a size adapted to positively grip and pull tow under tension, the third roll cooperating with one of said two rolls to form therebetween a second nip, of a size larger than said first nip and appropriate for pulling tow from the first nip while allowing a predetermined tow slippage.

3. Tow feeding apparatus comprising a first roll, a second roll and a third roll mounted in fixed spaced relation on substantially parallel axes to provide a first tow pulling nip between the first and second rolls and a second tow pulling nip between the second and third rolls, and means for driving all three rolls at a common surface speed, the first nip being adapted for positive pulling of tow in the absence of any substantial tow slippage and the second nip being of a larger size than the first nip and being adapted to pull tow from the first nip across the surface of the second roll, and being adapted to permit a slippage of tow passing therethrough of the order of about 5%.

4. Apparatus as defined in claim 1 in which two nips are formed by three rolls.

5. Apparatus for pulling tow comprising a pair of cooperating driven rolls, said rolls being spaced to form a fixed tow gripping nip therebetween, and a third driven roll cooperating with one of the rolls of said pair to form a second tow gripping nip therebetween, said three rolls being driven at a substantially common surface speed and being so constructed and spaced that said second nip allows more linear tow slippage than the said first nip.

References Cited in the file of this patent UNITED STATES PATENTS 71,832,034 Lashar Nov. 17, 1931 r 2,263,712 Wrigley et a1 Nov. 25, 1941 2,731,262 Morrow Jan. 17, 1956 2,947,060 Umstatt Aug. 2, 1960 3,018,608 Kileekanim et a]. Jan. 30, 1962 3,042,373 Berkman July 3, 1962 

5. APPARATUS FOR PULLING TOW COMPRISING A PAIR OF COOPERATING DRIVEN ROLLS, SAID ROLLS BEING SPACED TO FORM A FIXED TOW GRIPPING NIP THEREBETWEEN, AND A THIRD DRIVEN ROLL COOPERATING WITH ONE OF THE ROLLS OF SAID PAIR TO FORM A SECOND TOW GRIPPING NIP THEREBETWEEN, SAID THREE ROLLS BEING DRIVEN AT A SUBSTANTIALLY COMMON SURFACE SPEED AND BEING SO CONSTRUCTED AND SPACED THAT SAID SECOND NIP ALLOWS MORE LINEAR TOW SLIPPAGE THAN THE SAID FIRST NIP. 